SMTP beyond initial configuration

I'm not clear on what you're trying to accomplish here.  Are you just trying to set up the SMTP server so that it can relay email from programs on this machine or others in your DMZ to another specific email server?  Or trying to set it up so that various users can send email to anywhere, and if so why?  Are you sending out for a specific domain?  I may be able to provide some more specific advice when I understand better.

In general, to keep from being blocked by spam filters:
 - don't send out spam
 - have your DNS records in order.  For a sending server, this means having a PTR record for the IP you're sending from, and for the name in the PTR record have an A record that points back to the same IP.
 - check blacklists to make sure your IP isn't already on any blacklists for whatever reason

Currently the email provider we use has to many security restriction enabled for simple web forms and server/event logs to email up with updates. We deal a lot with HIPAA information so we have requested all the security. We have a few internal websites and servers that we would like to be able to send email to us that won’t contain any special information. We set up the SMTP server just for those devices. I have restricted access to it by ipaddress but I would like a little more security just to be safe. The Lead admin does not want to use a 3rd parties SMTP server like Google or what not so he wants me to set up an SMTP server.

I will restrict by ip address and use the firewall to stop smtp request from outside of my network.

Thanks for the help